libnvdimm: control (ioctl) messages for nvdimm_bus and nvdimm devices

Most discovery/configuration of the nvdimm-subsystem is done via sysfs
attributes.  However, some nvdimm_bus instances, particularly the
ACPI.NFIT bus, define a small set of messages that can be passed to the
platform.  For convenience we derive the initial libnvdimm-ioctl command
formats directly from the NFIT DSM Interface Example formats.

    ND_CMD_SMART: media health and diagnostics
    ND_CMD_GET_CONFIG_SIZE: size of the label space
    ND_CMD_GET_CONFIG_DATA: read label space
    ND_CMD_SET_CONFIG_DATA: write label space
    ND_CMD_VENDOR: vendor-specific command passthrough
    ND_CMD_ARS_CAP: report address-range-scrubbing capabilities
    ND_CMD_ARS_START: initiate scrubbing
    ND_CMD_ARS_STATUS: report on scrubbing state
    ND_CMD_SMART_THRESHOLD: configure alarm thresholds for smart events

If a platform later defines different commands than this set it is
straightforward to extend support to those formats.

Most of the commands target a specific dimm.  However, the
address-range-scrubbing commands target the bus.  The 'commands'
attribute in sysfs of an nvdimm_bus, or nvdimm, enumerate the supported
commands for that object.

Cc: <linux-acpi@vger.kernel.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: Nicholas Moulin <nicholas.w.moulin@linux.intel.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 35 insertions, 3 deletions

diff --git a/drivers/nvdimm/dimm_devs.c b/drivers/nvdimm/dimm_devs.c
index 51ea52cc2079..c3dd7227d1bb 100644
--- a/drivers/nvdimm/dimm_devs.c
+++ b/drivers/nvdimm/dimm_devs.c
@@ -12,6 +12,7 @@
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/device.h>
+#include <linux/ndctl.h>
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/fs.h>
@@ -33,7 +34,7 @@ static struct device_type nvdimm_device_type = {
 	.release = nvdimm_release,
 };
 
-static bool is_nvdimm(struct device *dev)
+bool is_nvdimm(struct device *dev)
 {
 	return dev->type == &nvdimm_device_type;
 }
@@ -55,12 +56,41 @@ EXPORT_SYMBOL_GPL(nvdimm_name);
 
 void *nvdimm_provider_data(struct nvdimm *nvdimm)
 {
-	return nvdimm->provider_data;
+	if (nvdimm)
+		return nvdimm->provider_data;
+	return NULL;
 }
 EXPORT_SYMBOL_GPL(nvdimm_provider_data);
 
+static ssize_t commands_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	int cmd, len = 0;
+
+	if (!nvdimm->dsm_mask)
+		return sprintf(buf, "\n");
+
+	for_each_set_bit(cmd, nvdimm->dsm_mask, BITS_PER_LONG)
+		len += sprintf(buf + len, "%s ", nvdimm_cmd_name(cmd));
+	len += sprintf(buf + len, "\n");
+	return len;
+}
+static DEVICE_ATTR_RO(commands);
+
+static struct attribute *nvdimm_attributes[] = {
+	&dev_attr_commands.attr,
+	NULL,
+};
+
+struct attribute_group nvdimm_attribute_group = {
+	.attrs = nvdimm_attributes,
+};
+EXPORT_SYMBOL_GPL(nvdimm_attribute_group);
+
 struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
-		const struct attribute_group **groups, unsigned long flags)
+		const struct attribute_group **groups, unsigned long flags,
+		unsigned long *dsm_mask)
 {
 	struct nvdimm *nvdimm = kzalloc(sizeof(*nvdimm), GFP_KERNEL);
 	struct device *dev;
@@ -75,12 +105,14 @@ struct nvdimm *nvdimm_create(struct nvdimm_bus *nvdimm_bus, void *provider_data,
 	}
 	nvdimm->provider_data = provider_data;
 	nvdimm->flags = flags;
+	nvdimm->dsm_mask = dsm_mask;
 
 	dev = &nvdimm->dev;
 	dev_set_name(dev, "nmem%d", nvdimm->id);
 	dev->parent = &nvdimm_bus->dev;
 	dev->type = &nvdimm_device_type;
 	dev->bus = &nvdimm_bus_type;
+	dev->devt = MKDEV(nvdimm_major, nvdimm->id);
 	dev->groups = groups;
 	if (device_register(dev) != 0) {
 		put_device(dev);